A technology for detecting a temperature of a dummy substrate based on a signal received by a sensor coil is known in which a dummy substrate having a temperature detecting element connecting a coil or an antenna to a crystal oscillator is placed on a resin sheet on which the sensor coil is disposed.    [Patent Document 1] Japanese Laid-open Patent Publication No. 2008-139256
However, according to the conventional technique as described above, it is difficult to detect a state of the crystal oscillator before a transition to an output stop state (for example, clock stop) based on the signal received by the sensor coil. It is noted that the output stop of the crystal oscillator may occur suddenly due to abnormality of the crystal oscillator or the like.